Glow discharge starter tube with hydrocarbon-rare gas fill

ABSTRACT

A glow discharge starter tube having within a sealed envelope gaseous atmosphere consisting of a rate gas and a gaseous hydrocarbon.

United States Patent Kamei et al. Aug. 1, 1972 [541 GLOW DISCHARGE STARTER TUBE 51 161. CI .1101 j 17/20 WITH HYDROCARBON-RARE GAS [58] Field of Search ..313/224, 151, 210, 27, 93 FILL [72] Inventors: Taketo Kamei; Kouichi Miyazaki, [56] References Cited b th fY k k ,J a apan UNITED STATES PATENTS [73] Asslgneez Tokyo Shibaura Electric Co., Ltd.,

a] 6 "3 l x 3,213,312 10/1965 Crowe et a1. ..313/93 UX [221 1970 2,837,677 6/1958 Hendee et al ..313/93 [21] Appl. No.: 70,758 2,678,979 5/1954 Beese ..313/224 X Related US. Application Data Primary Examiner-Roy Lake Assistant Examiner-Palmer C. Demeo [63] Continuation-impart of Ser. No. 671,082, Attorney-George B. Oujevolk Sept. 27, 1967, abandoned.

. [57] ABSTRACT [30] Foreign Appllcatlon Priority Data A glow discharge starter tube havlng within a sea1ed Sept. 30, 1966 Japan ..4l/64328 envelope gaseous atmosphere consisting of a rate gas 52 us. 01. .313/151, 313/210, 313/224, and a gasews hydmcarbm' 3 7/2 7 Claims, 18 Drawing figures PATENTE'DAus 1 1912 SHEET 1 OF 8 FIG] mOm mSE. uO QOEmm PRIOR ART m W n 5600 THE NUMBER OF REPETITION OF THE LIGHTING OPERATION F I G.

100 TUBE VOLTAGE (VOLT) 3 hzmmmDu mmDP m A A 1 5 J {a A N w k .4 w a fim m 0 0 O 8 0 7 m M Q F B 0 4 m mm 0T ,OE I 6 RE W0 m ll m Wm NL ww v TT 0 0 0 O 5 2 1 2.402 mo Do ozFmfim mwmqfumfi PIIIENIEDAuc' I I972 SHEET 2 [IF 8 FIG.5

THE NUMBER OF REPETITION OF THE LIGHTING OPERATION FIG.6

THE NUMBER OF REPETITION OF THE LIGHTING OPERATION PATENIEnm Hm j 3.681.639

SHEET 3 BF 8 I STARTING VOLTAGE 10o so so 40 20 o ORGAN'ICGA'S m ARGON FIGQ8 RECLOSURE PAIEIII'EIIIIII' I I912 3.681.639

SHEET 0F 8 1 C3H8 IN ARGON 2 C2H6 IN ARGQN 3 CH4 IN ARGON RATED VOLTAGE 200V LAMP FL- STARTING TIME (5 N FILLING GAS PRESSURE (TORR) FIG. 12

VOLTAGE (V') MIN. RECLOSURE VOLTAGE FILLING GAS PRESSURE (TORR) rMJZ PATENTEDAuc 1 I972 SHEET 6 OF 8 FIG.13

2'0 ORGANIC GAS IN NEON 1 '2 3 4 S 6 '7 8 93 ORGANIC GAS IN NEON m rm 2;; Eummnu Rod PATENTEDAuc 1 I972 FIG.15

RECLOSURE VOLTAGE (V) STARTING TIME 9 P SHEET 70F 8 1 C3H8 1.0% IN NEON 2 C2H6.1.5% IN NEON "3 CH4 2.0% IN NEON GAS PRESSURE (TORR) 1 C3H8 1.0 IN NEON 2 C2H6 1.5 70 IN NEON IN NEON 2'0 40 60 GAS PRESSURE TORR) INVENTORqQ BY E. Y

PAIENTEDAus' 1 I972 SHEET 8 0F 8 3 4 GASEOUS HYDROCARBON IN NEON to 5 L. z p azoomwvmszh OZFEEM 2 GASEOUS HYDROCARBON IN NEON o 0 m w 63 mo 5o wmnmodmm INVEXTORJJ GLOW DISCHARGE STARTER TUBE HYDROCARBON-RARE GAS FILL CROSS-REFERENCE TO RELATED APPLICATIONS v This is a continuation-impart of application Ser. No 671,082, filed Sept. 27, 1967, now abandoned.

BACKGROUND OF THE. INVENTION This invention relates to glow discharge devices, and more particularly to a glow discharge starter tube containing an improved gaseous medium to improve its characteristics- In a glow discharge starter tube having a sealed envelope in which a rare gas such as argon is corporated alone, the discharge starting voltage is not uniform and the amount of glow current at a rated voltage is small; and the period of time for starting is largely changed in the initial stage of life cycle. g

The discharge starting voltage is rapidly lowered as the lamp lighting operation repeats itself and reaches a value less than that of a reclosuring voltage. This causes the glow starter to re-discharge with the result that it is put off during operation. Namely, the glow starter is usually connected toa power source in parallel with the lamp, so that the lamp voltage is impressed across the glow starter when the glow starter operates normally and the lamp is lit. Thus, when the re-starting voltage of the glow starter is equal to or under the lamp voltage, the glow starter re-starts its operation after lamp lighting to permit the lamp to repeat lighting operations. This re-starting voltage is called reclosure voltage and must exceed the lamp voltage. The lowest re-starting voltage of the glow starter which is determined by the wattage of the lamp and circuit conditions is called minimum reclosure voltage. This is due to the fact that the glow starter is apt to easily discharge since an oxide deposited on electrodes in particular an oxide deposited mainly on a bi-metallic element used as one of such discharging electrodes is cleaned up when a discharge is occurred. As a resultthe glow starter will re-discharge when the value decreases less than the reclosuring voltage and the fluorescent lamp repeats to stop and start lighting.

Three methods have been proposed heretofore to avoid these deficiencies. One of them is to deposit an aluminum powder on the stem of the glow starter. Another method is to spatteran active metal such as aluminum, cadmium or zinc on the electrodes. The third method is to incorporate radioactive substances within a sealed envelope. These prior art methods present problems in the process of manufacture and in the cost of material, and still have defects in the characteristics of the lamps.

SUMMARY OF THE INVENTION An object of this invention is to provide a glow discharge starter tube having improved characteristics throughout its useful life. I

Another object of this 'invention is to provide a glow discharge starter tube having relatively low starting voltage, high reclosure voltage and short period of time for starting and which can be maintained in a stabilized condition over along period of use.

V will serve to form the this invention by providing These objects may be attained in accordance with within a ow dis starter tube a low pressure gaseous atmo s phere i s: mg of a mixture of an amount of a rare gas and an amount of a gaseous hydrocarbon. The rare gas may be at least one element selected from the group consisting of argon and neon. The advantages of using argon and neon reside in the fact that they are relatively easily available, the property is relatively stable as compared with other rare gases, and that they have excellent utility. The gaseous hydrocarbon may be at least one hydrocarbon selected from the group consisting of methane (CPL). ethane Z Q). p p a a) acetylene, ethylene, vapored benzene and Sublimated naphthalene. A mixture of gaseous hydrocarbon (CH C l-l C l-I and argon is already put into practical use for a radioactive rays counter in the field of Townsend discharge. In the field of glow discharge, however, this has not been applied to a usual discharge tube by reason of the fact that such an organic gas loses its function by being easily resolved. According to this invention, the disolution of the gas is effectively utilized to improve the property of a starter tube (one mode of a discharge tube). Among the gaseous hydrocarbons described above, those having a less carbon content gaseous mixture that can best be used.

BRIEF EXPLANATION OF THE DRAWINGS FIG. 1 shows thegeneral characteristics of a conven- FIG. 7 shows the starting voltage composition characteristic of a gaseous medium according to this invention;

FIG. 8 shows the reclosure voltage-composition characteristic thereof; I

FIG. 9 shows the starting time-composition ratio characteristic of a glow starter of this invention;

FIG. 10 shows the composition ratio-glow current characteristic of a glow starter of this invention;

FIG. 11 shows the starting time-filling gas pressure characteristic of a glow starter of this invention;

FIG. 12 shows the reclosure voltage-filling gas pres sure characteristic of the glow starter of this invention;

FIG. 13 shows the starting voltage-composition ratio characteristic of a glow starter embodying still another modification of this invention;

FIG. 14 shows the glow current-composition ratio characteristic of the glow starter of FIG. 13;

FIG. 15 shows the starting time-filling gas pressure characteristic of a glow starter embodying a further modification of this invention;

FIG. 16 shows the reclosure voltage-filling gas pressure characteristic of the glow starter of FIG. 15;

FIG. 17 shows the starting time-composition ratio filling gas pressure is set at mm Hg; and

FIG.. 18 shows the reclosure voltage-composition ratio characteristic of the glow starter of FIG; 17.

DETAILED DESCRIPTION OF THE INVENTION The ordinary characteristics of a conventional glow starter will first be described with reference to FIG. 1, which shows, among various characteristics of a glow starter tube, the discharge starting voltage characteristic within the range of 120-220V as shown by the curve B. As shown by a curve A in FIG. I, a period of starter tube containing the gaseous hydrocarbon can be operated with an increased tube current when comtime for starting of the glow starter (not shown) used,

for example, in a 200 volt fluorescent lamp exceeds a predetermined maximum starting period, for example, seconds, shown by a dotted line a at the initial stage in the life of the lamp, but is gradually shortened to come below the set level a representing the maximum rated period, as the lighting operation of the lamp is repeated and hence the number thereof increased. A discharge starting voltage is decreased, as shown by a curve B, with the increase in the number of repetition of the lighting operation till it drops below the value of a re-starting voltage indicated by a dotted line b. Since the starting time tends to be excessively varied for the initial stage of a few thousand times of operation and to become gradually stable thereafter, the initial period of excessive variation is usually excluded from that of the utility period in order that the tube'may stably operate. The stabilization of the starting time is attained when the electrode is cleaned up by discharge. This clean-up, on the other hand, serves to lower the reclosure voltage in addition to the lowering of the discharge starting voltage, and the fluorescent lamp repeats lighting when the reclosure voltage falls below the lamp voltage, with the result that the satisfactory utility period is shortened. In order to minimize such excessive change in the starting time and to stabilize the characteristic, the various measures mentioned above are known. According to this invention, a different measure is employed toachieve the same purpose.

When a gaseous hydrocarbon is sealed in an arc discharge device exemplified by a metallic vapor discharge lamp, such as a fluorescent lamp or a mercury lamp, the sealed hydrocarbon is readily resolved into carbon and hydrogen, and the resolved carbon is combined with oxygen present in the sealed envelope to form carbon monoxide and carbon dioxide. The oxygen is derived, by discharge, from an oxide produced during the course of manufacturing the glow discharge tube. These CO and CO will gradually till the envelope as a discharge repeatedly occurs for a long time and cause a discharge not to easily take place, with a result that the starting voltage is elevated.

According to this invention, a gaseous hydrocarbon having its properties above-mentioned is sealed in a discharge switch such as a glow starter containing argon or neon. The sealed gaseous hydrocarbon will be resolved into carbon and hydrogen even in a glow discharge region. The carbon will then be combined with oxygen within the envelope to form carbon monoxide and carbon dioxide thereby to elevate the starting voltage. This elevation in voltage compensates the self-cleaning up action of .the electrodes which functions to lower the starting voltage, so that the discharge starting voltage can be maintained at substantially a constant value. Further the glow discharge pared with one in which a rare gas such as argon or neon is alone used, since ionization potential for a hydrocarbon atmosphere is low. It will be appreciated from FIG. 2. that acurve D showing a tube current for a glow discharge starter tube containing a gaseous mixture of argon and hydrocarbon exhibits a sharp buildup in comparison with a similar curve C for a discharge device containing argon or neon alone.

Such properties of gaseous hydrocarbon that a tube current is increased and shorten the starting time at the initial stage in the life cycle of the device and that a decrease of discharge starting voltage is prevented at the succeeding stage are important advantageous factors in the glow starters for fluorescent lamps. FIG. 3 illustrates one embodiment of this invention wherein the glow starter comprises a sealedenvelope l, a stem 4 mounted in said envelope, two electrodes 2 and 3 mounted on said stem and connected to lead-ins, one being a stationary one 3 and the other having a bimetal 2 which engages and disengages the stationary electrode 3, and alow pressure gaseous atmosphere within said envelope, said atmosphere being a pressure of 30 to 50 millimeters of mercury and being a gaseous mixture of for example, percent, by volume, of argon and 10 percent, by volume, of propane (C l-I which is one formed of hydrocarbon. Said electrodes 2 and 3 upon initiation of current flow comes in contact maintaining only for a predetermined starting period, said period being undesirably subject to change with variations in quantity of carbon oxides within said envelope 1. The general repetition characteristics of the glow starter are shown in FIGS. 4 to 6. In the figures, curves E represent various characteristics of the glow starter of thisinvention wherein the gaseous mixture consisting of 90 percent by volume of argon and 10 percent by the curve F irrespective of the increase in the number of lighting operations.

In FIG. 5, the required lighting period is shorter in the curve B than in the curve F. This will indicate that the effect attained by incorporation of propane gas is.

conspicuous. Further, it will be seen that the reclosure voltage represented by the curve E in FIG. 6 is considerably higher than that represented by the curve F and shown in a concave upward curvature. This will ex: plain that the characteristics or functions of the glow starter can be maintained in a suitable condition over repeated use and hence for along time, due to the fact that the self-cleaning up action of the electrodes 2, 3 and carbon monoxide and carbon dioxide produced as a result of resolution of the sealed propane gas act independently to compensate the value of the discharge starting voltage and keep it constant as far as possible.

FIGS. 7 and 8 show variations in the value of the discharge starting voltage and the reclosure voltage in the case of a modified glow starter of this invention in which the ratio of the sealed gaseous atmosphere, viz. argon and hydrocarbon (CI-I C I-I C I-I is changed under a lower gaseous pressure maintained at 20 mmHg. Use of CH C H or C l-l is preferred since a gas of high carbon content is unsatisfactory in view of the defect that the gaseous mixture tends to be separated into unit gases when it is to be stored in a container during the manufacture of the tube. It will be seen that the discharge starting voltage is relatively low and maintained below a value of 200 volts, and yet the reclosure voltage is high and maintained well above a value of said minimum reclosure voltage, particularly when argon-hydrocarbon ratio is selected between the range of 40 60 and 99 1 in volume percent.

FIGS. 9 and 10 show characteristics of the tube in which argon is mixed with methane, ethane or propane with a different mixing ratio. In particular, FIG. 9 shows the mixing ratio-starting time (second). characteristic when the starting voltage is equal to a rated voltage of 200V. Excellent results of less than 4 seconds of the starting time are obtained with the mixing ratio of methane, ethane, or propane with respect to argon ranging from 1 to 30 percent. FIG. 10 shows a change of the glow current (mA) with respect to the mixing ratio. It will be apparent that excellent results of above mA in the glow current are obtained with the mixing ratio of 1 to 35 percent.

FIG. 11 shows the relationship between the filling gas pressure and the starting time when the argon contains, respectively percent of CH.,, 15 percent of C I-I and 10 percent of C H The lamp used is a fluorescent lamp operated at 40 watt and having a rated voltage of 200V. As will be apparent from the figure, when the starting time is selected to a practical limit of less than 5 seconds, satisfactory data are obtained at a filling gas pressure of 10-70 mmI-Ig.

FIG. 12 shows the relationship between the filling gas pressure and the reclosure voltage of the lamp of FIG. 11 which is set to have the same mixing ratio. The minimum reclosure voltage of the lamp is 132 volts and the filling gas pressure is 10-60 mmI-Ig, which sufficiently support utility of the lamp.

Argon is used as a rare gas in the above examples. But similar effects can be obtained when neon is used in place of argon.

FIG. 13 shows a starting voltage-composition ratio characteristic curve of a glow starter embodying another modification of this invention. In the figure, the starting voltage is increased in either case of CH C H or C l-I as the increase of its ratio to neon, similarly to argon of FIG. 7.

FIG. 14 shows a glow current-composition ratio characteristic curve of a glow starter of FIG. 13. It will be seen that the glow current shows its maximum value in a very small region where the ratio to neon is 0.1 percent to 5 percent.

FIG. 15 are currents showing a variation in the starting time when the filling gas pressure within a starter tube for a 135 to 155V, 32W fluorescent lamp is changed in the range of 20 to 110 mmHg, in which curve 1 represents the case when neon contains 2.0 percent of CH curve 2 the case when it contains 1.5 percent of C H and curve 3 the case when it contains 1.0 percent of C 11 respectively. If the practical starting time is set to less than 5 seconds, a pressure in the range of 40 to I10 mmI-Ig can be used. In particular, a pressure of mmI-Ig results in an excellent starting time of about 3 seconds.

FIG. 16 shows the relationship between the filling gas pressure and the reclosure voltage of a starter similar to the one shown in FIG. 15. Although the minimum reclosure voltage of the lamp is about volts, the curve shows the value of a practical reclosure voltage of about to volts at a pressure ranging from 20 to 100 mmHg.

FIG. '17 shows a starting time-composition ratio when the filling gas pressure in FIG. 15 is 70 mmHg, and represents the practical value when the starting time is less than 4 seconds with the ratio of 0.1 to 3 percent.

FIG. 18 shows a similar view when the filling gas pressure in FIG. 15 is 70 mmHg, and represents the minimum reclosure voltage of an excellent value of above 95 volts.

of CH C I'I or C l-I which are mixed in the ratio of 99.1 0.1 to 40 60 in volume percent.

As will be apparent from the data given above, when comparison is given to the envelope filled with argon and gaseous hydrocarbon and to the one filled with neon and gaseous hydrocarbon, the starting voltage or the reclosure voltage exhibits a high value when argon is used. Therefore, when a relatively high operating voltage is desired a starter containing argon may be used, while a starter containing neon is preferably employed when the operating voltage is low. It is thus possible to obtain glow discharge starter tubes of desired characteristics appropriate to particular applications.

What we claim is:

1. A glow discharge starter tube comprising a sealed envelope, at least two electrodes mounted therein, one of which is stationary and the other one of which constitutes a movable metallic element; upon initiation of current flow said electrodes maintaining contact with each other, for a predetermined period which is subject to change with variation in quantity of carbon oxides within said envelope; and means for regulating said quantity so as to maintain said starting period substantially constant; said means comprising a gas fill within said envelope which consists of a rare gas-gaseous hydrocarbon mixture at a pressure of about 10 to I10 millimeters of mercury, the rare gas-gaseous hydrocarbon ratio of said mixture being between 40:60 and 99.9:0.l in volume percent.

2. The glow discharge starter tube according to claim 1 wherein said rare gas is argon, said hydrocarbon is one selected from methane, ethane and propane, and the mixture is filled at a pressure of about 10 to 70 millimeters of mercury, the argon-hydrocarbon ratio of said mixture being 40 to 99: 60 to l in volume percent.

3. The glow discharge starter tube according to claim 2 wherein the pressure of said argon and hydrocarbon mixture is about 30 to 50 millimeters of mercury.

4. The glow discharge starter tube according to claim 2 wherein said hydrocarbon is propane and the mixture is filledat a pressure of millimeters of mercury.

5. The glow discharge starter tube according to claim 1 wherein said rare gas is neon, said hydrocarbon being one selected from methane, ethane and propane, and mixed gas filling at a pressure of about 40 to 110 millimeters of mercury, the neon-hydrocarbon ratio of said mixture being 95 to 99.9 5 to 0.1 in volume percent.

6. The glow discharge starter tube according to claim 5 wherein the pressure of said neon and hydrocarbon mixture is at 70 millimeters of mercury.

7. A glow discharge tube comprising in combination: 

2. The glow discharge starter tube according to claim 1 wherein said rare gas is argon, said hydrocarbon is one selected from methane, ethane and propane, and the mixture is filled at a pressure of about 10 to 70 millimeters of mercury, the argon-hydrocarbon ratio of said mixture being 40 to 99: 60 to 1 in volume percent.
 3. The glow discharge starter tube according to claim 2 wherein the pressure of said argon and hydrocarbon mixture is about 30 to 50 millimeters of mercury.
 4. The glow discharge starter tube according to claim 2 wherein said hydrocarbon is propane and the mixture is filled at a pressure of 20 millimeters of mercury.
 5. The glow discharge starter tube according to claim 1 wherein said rare gas is neon, said hydrocarbon being one selected from methane, ethane and propane, and mixed gas filling at a pressure of about 40 to 110 millimeters of mercury, the neon-hydrocarbon ratio of said mixture being 95 to 99.9 : 5 to 0.1 in volume percent.
 6. The glow discharge starter tube according to claim 5 wherein the pressure of said neon and hydrocarbon mixture is at 70 millimeters of mercury.
 7. A glow discharge tube comprising in combination: a. a sealed envelope; b. a stationary first electrode within said envelope; c. a thermo-movable metallic second electrode in make and break contact with said first electrode having a make contact period depending on the quantity of carbon oxides within said envelope, and, d. means for regulating said carbon oxide quantity comprising a mixture of a rare gas and a hydrocarbon gas at a pressure as 10 to 110 millimeters of mercury, the ratio of rare gas to hydrocarbon gas being between 40:60 and 99.9:0.1 in volume percent. 